摘要
三乙氧基硅丙胺与介孔分子筛MCM-41表面的羟基在甲苯中回流反应得到氨丙基官能团化的MCM-41,再利用氨基与Salen-Mn(Ⅲ)上的活性酯基生成酰胺键,将手性Salen-Mn(Ⅲ)配合物负载到MCM-41上,实现了手性均相催化剂的多相化.分别利用FT-IR,DRUV-Vis,XRD,ICP和N2吸附等手段对负载型催化剂进行了表征.结果表明,手性Salen-Mn(Ⅲ)配合物成功负载到MCM-41上,但MCM-41和手性Salen-Mn(Ⅲ)配合物固有的结构保持不变.以次氯酸钠和间氯过氧苯甲酸为氧化剂,考察了负载型催化剂对1,2-二氢萘不对称环氧化反应的催化性能,结果表明,负载型催化剂的催化活性比相应均相催化剂的低,但对映体选择性有所提高.在NaClO/PyNO氧化剂体系中20℃反应12h,1,2-二氢萘环氧化物的收率达45.9%,对映体过量值为84.3%.负载型催化剂在循环使用5次后Mn的流失达34%.
MCM-41 was functionalized with 3-aminopropyl groups by the reaction of hydroxyl groups on the MCM-41 surface with 3-aminopropyltriethoxysilane being refluxed in toluene. By employing the reaction of amino groups with active ester groups on the chiral Salen-Mn（ Ⅲ ） complex, the homogeneous chiral Salen-Mn （Ⅲ） complex was heterogenized. The supported catalyst was characterized by FT-IR, DR UV-Vis, XRD, ICP, and N2 adsorption. The results indicated that the complex was supported on MCM-41 and the native structure of MCM-41 was maintained. The supported catalyst was applied to the enantioselective epoxidation of 1,2- dihydronaphthalene using NaCIO and m-chloroperbenzoic acid as oxidants. The results confirmed that the activity of the supported catalyst was lower than that of the homogeneous chiral Salen-Mn（ m ）. However, its enantioselectivity was higher than that of the homogeneous one. A yield of 45.9 % and ee of 84.3 % of epoxide were obtained when 1,2-dihydronaphthalene was oxidized by NaCIO for 12 h at 20 ℃ in the presence of the pyridine nitrogen oxide. About 34 % of manganese leaching was observed after the suooorted catalyst was run 5 times.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2007年第1期85-90,共6页
基金
国家自然科学基金(20376017)
